Not applicable.
Not applicable.
The invention relates to a process for filling a mixture of at least two monomeric and/or oligomeric components into a container, which mixture, after discharge from the container, polymerizes with at least partial volume increase, and a container containing a mixture filled under pressure and consisting of at least two monomeric and/or oligomeric components.
Polyurethane foams are widely used. Polyurethane foams are used in particular in the building industry, for example as insulating material or sealing material for windows and doors. The foam components required for this purpose are provided in containers or cans. Before the polyurethane foam is discharged, it is necessary to mix the components of the can thoroughly by shaking since the individual components, such as, for example, polyol, isocyanate and the blowing gases and additives, are present separately in the can under pressure. Only after thorough mixing of the components is it possible to discharge the polyurethane foam, which expands and cures after discharge. In addition, such containers have the disadvantage that, right at the beginning or after slight emptying, only overhead work is possible for further discharge of the polyurethane foam, i.e. the container must be held with the discharge valve pointing downwards in order to discharge the foam. This makes it considerably more difficult to carry out the activity. A further substantial disadvantage of these sales units is that a considerable proportion of polyol and isocyanate remains in the can and can no longer be discharged because the blowing gas has already been consumed. Consequently, the consumer can process only xc2xe of the amount of polyurethane foam purchased. Furthermore, owing to the only partial emptying, the toxic component isocyanate remains in the container so that the disposal of such cans is complicated and expensive and gives rise to environmental pollution.
It is therefore the object of the invention to provide a process for filling a mixture of at least two components into a container, which mixture, after discharge, polymerizes with at least partial volume increase, and a container containing a mixture filled under pressure, so that virtually complete discharge of the medium from the container is permitted.
This object is achieved by a process for filling a mixture of at least two monomeric and/or oligomeric components into a container, which mixture, after discharge from the container, polymerizes with at least partial volume increase, comprising the following steps: feeding the at least two components to be mixed to a mixing zone, mixing the at least two components under pressure in the mixing zone, and filling the mixture under pressure into an envelope in the container. This object is also achieved by a container for discharging a mixture of at least two monomeric and/or oligomeric components which, after discharge from the container, polymerize with at least partial volume increase, comprising an interior that is subjected to superatmospheric pressure, an envelope arranged in the interior, and a valve that clinches the bag to a container orifice in a medium-tight manner, wherein a mixture consisting of the at least two components is introduced under pressure into the envelope.
This process permits virtually complete emptying of an envelope provided in the container and intended for holding a mixture of at least two monomeric and/or oligomeric components. Surprisingly, it has been found that the mixture of these components is maintained under pressure and separation into the individual components does not take place. Consequently, uniform distribution of the at least two components can take place, resulting in virtually complete discharge. Furthermore, the mixture can surprisingly be kept in a liquid phase, with the result that discharge of the mixture is permitted even after prolonged storage, without polymerization taking place in the container.
This is particularly advantageous especially when filling the container with a polyurethane foam, since the component isocyanate is toxic and, as a result of the virtually complete discharge, simple and environmentally compatible disposal of such containers is ensured. Consequently, not only is the degree of use of the containers filled by the process considerably increased. In addition, the filling of containers by means of this process makes it possible to discharge the mixture consisting of at least two monomeric and/or oligomeric components in any desired position and location of the container. This leads to greater flexibility during use and to a simplification of discharge of the mixture, in particular of a polyurethane foam, which is preferably used in the building industry. A reduction in the time required for processing can thus be achieved.
According to a development of the process, it is intended that the mixing zone be in the form of a mixing container in which the components are subjected to at least a superatmospheric pressure which is such that the remaining mixture is kept in the liquid phase when a mixing container has been almost completely emptied. This makes it possible to suppress separation of the individual components, so that foaming of one of the components is also prevented. The superatmospheric pressure is such that the individual components of the mixture are always kept in the liquid phase, even when there is a pressure drop owing to virtually complete emptying of the mixing container.
As an alternative to a mixing container in the form of a mixing zone, it is also possible to provide a continuous homogenization zone or mixing zone which permits uniform thorough mixing with simultaneous or successive feeding of the individual components. Even in the case of continuous thorough mixing and removal of the mixture from the mixing zone, superatmospheric pressure which once again keeps the mixture in the liquid phase is built up owing to the amount of mixture to be removed in relation to the feed of the individual components.
According to a further development of the invention, it is intended that the mixing zone be cooled, preferably to a temperature of less than 50xc2x0, during the thorough mixing of the at least two components. As a result, so-called boiling of the components can be avoided. This is of particular importance especially with the use of polyurethane foam. As a result of the cooling, it is also possible to achieve uniform thorough mixing. The cooling of the mixture in the container and the magnitude of the superatmospheric pressure to be applied in the container are related to the components to be mixed. These parameters are set and tailored to one another in such a way that the mixture is removed in a liquid phase from the mixing zone.
According to a further development of the invention, it is intended that each of the at least two components is fed in succession to the mixing zone and a measurement of the quantity of the component fed in is carried out. By weighing the mixing container, the amount of the component fed in can be determined and also recorded. Thus, for example when a mixing container has a volume of 300 l, portioning of the respective components accurately to 100 g may be permitted, with the result that a very exact composition of the formulation is achieved. Consequently, the quality of the product to be discharged can be established exactly in its reaction after the discharge. The product quality is thus increased.
According to a further development of the invention, it is intended that complete thorough mixing of the components is effected in a first phase in the mixing zone and a calming phase is carried out thereafter. Owing to the thorough mixing with stirring tools or the like, preferably by means of a stirrer having one or more propellers, the small bubbles formed on the stirring tools during the thorough mixing can escape from the mixture and migrate, so that exclusively the mixture present in the liquid phase is filled into the container.
According to a further development of the invention, it is intended that the mixture be fed by a delivery pump to a filling station for portioning the amount to be filled. By means of the delivery pump, the pressure is maintained or increased and the prepared mixture is transferred under pressure to a filling head of the filling station for portioning of the amount to be filled. Advantageously, it can be ensured that further additives are also mixed in by means of the delivery pump.
This process according to the invention is used for filling components with the formation of a polyurethane foam into containers. In particular, the components polyol, isocyanate and various additives, such as, for example, flameproofing agents and anti-ageing agents, as well as various gases are advantageously used for this purpose. The use of compressed air as blowing gas is particularly advantageous since this is an environmentally friendly use of blowing gas.
Alternatively, further monomeric and/or oligomeric components which serve for the formation of foamed plastics can also be used. For example, polystyrene and styrene copolymers, rigid and flexible PVC, polycarbonates, polyolefins, polyisocyanurates, polycarbodiimides, polymethacrylates and polyamides are also suitable in addition to polyurethane for the preparation of foamed plastics.
The use of a container according to the invention makes it possible to keep the mixture in a liquid phase, preferably under pressure, during storage until use and, due to the superatmospheric pressure, permits virtually complete or complete discharge. The discharge can also be effected in all possible positions of the container.